Managed switches aren't too much more than their unmanaged counterparts. More importantly, you'd need a firewall that supports it. Doesn't do you any good to have vlans if you don't have a firewall to enforce traffic between those zones. Getting a firewall is the expensive bit, unless you use an old computer and toss pfsense/opnsense on it, or you buy a baby soho firewall (~$150-$200)